This application proposes to investigate aldosterone effects on RNA and protein synthesis in both kidney and heart. The experiments are aimed at revealing whether aldosterone coordinately stimulates RNA and protein synthesis during the latent period of sodium resorption. Additional aims are to find the induced protein and to establish, on a biochemical basis, the effect of aldosterone in the heart. The experiments will determine the effect of adrenalectomy and the time-course of aldosterone action: nucleotide pool sizes, time required to reach maximum specific activity, and incorporation into different RNA species and their specific activity. Similarly, the effect of aldosterone on protein synthesis will be studied. The time required to reach a constant specific activity of the intracellular free amino acid, and its maximal specific activity, will be compared in the heart and kidney from adrenalectomized and hormone-treated, adrenalectomized rats. The incorporation of labeled amino acid into individual subcellular fractions including polyribosomes will be assessed. The proteins of the subcellular fractions will be solubilized and analyzed by gel electrophoresis followed by determination of the specific activity of each protein band, to reveal individual proteins whose synthesis has been stimulated. The potential effect of aldosterone on mitochondrial synthetic processes will be investigated by in vitro assay of RNA polymerase and amino acid incorporation into mitochondrial proteins. Since electrolyte imbalances are usually associated with abnormal levels of aldosterone, a better understanding of the basic mechanism of aldosterone action should provide more insight into these disease states. Also the potential role of aldosterone in cardiac ion transport may lead to a better understanding of certain cardic disorders and hypertension.